Normally, I'd agree with you, but I think this may be a special case:
1. The Conservatives got more votes overall than they have for many elections. What killed them was the collapse of the NDP, with likely 100% of those voters switching to the Liberals (they aren't likely Conservative voters in any scenario). Had that not happened, we would likely have seen a Conservative majority. Points for Poilievre.
2. Some say that they voted Liberal because they thought Carney would do a better job fighting Trump. But - you can't really fight Trump, at least not without doing (more) material damage to an economy which is so dependent on international trade and US trade in particular. And fighting Trump may just make things worse, which people may come to regret. People may come to see in pretty short order that Poilievre's approach may be the better one. More points.
3. Most importantly, in a minority government situation, we have no idea how long Carney will last, but it's likely not four years. To get a new leader elected and up and running could take too long, especially since there's no other realistic or waiting-in-the-wings number 1. So keeping Poilievre in the spot may make sense, at least for the foreseeable future. If we had a majority, I would agree with you.
4. Canada is the most divided than at any time I can recall (and I'm well into my 60s). If Carney continues with Liberal policies of the past, that will only get worse and again, people may wake up and see that the country is at risk not from external threats, but from internal ones. Poilievre would have been a better choice there.
5. Carney adopted an old Liberal trick - if your opponent has policies which are attractive to the electorate, take them as your own. He took Poilievre's two main policies - the carbon tax and the increase in the capital gains inclusion rate - and adopted them as his own. So the Conservatives had the right policies, they just couldn't make people see that those who adopt policies against their will are likely of the same opinion still. Points to Poilevre for reading the electorate here (but loses points for not being able to overcome the tried-and-true Liberal campaign tactic.)
Overall, I think that Poilievre did a reasonable job, given the very unusual circumstances of this election. I hope (and pray) that my fellow Canadians will soon wake up and see that re-electing those who are responsible for Canada's "lost decade" wasn't the bright idea they may have though it was yesterday. I'd give Poilievre a year and if Carney remains a likely winner between the two, then I'd push for a change. In the meantime, Poilievre needs to become and appear to become more "statesman" like.